During any given month, the average couple has a 15 to 25 percent chance of becoming pregnant. The key to using those odds in your favor is to know precisely when you are ovulating.
Every woman’s body is different. It is commonly believed that a woman will ovulate exactly during the middle of their cycle. In reality, women generally ovulate about 14 days before their next period. While that timeframe would indeed be mid-cycle for a woman with a 28-day cycle, some women have a cycle that can span as many as 32 days.1
Ovulation takes place when a mature ovarian follicle releases an ovum. It then travels down the fallopian tube. This is the ideal time to become pregnant, and if possible, it’s best to try to have sex as close to 12 hours before you release an egg as you can to maximize your odds of conception. Typically, the woman’s egg is only able to be fertilized for a period of 12 to 24 hours. That’s why it’s so important to have sex both in the days leading up to ovulation, and on the day on which you ovulate.
According to a study published in The New England Journal of Medicine, nearly all pregnancies occur within a six-day period which ends on the day of ovulation. The probability of conception ranges from approximately ten percent five days prior to ovulation to roughly 33 percent on the day of ovulation itself.
Only six percent of pregnancies occurred with sperm that was three or more days old.2
In other words, your chances of conception are far greater when you have sex during your ideal window of time, instead of having sex a little too early and hoping the sperm will stay alive long enough to fertilize the egg. [avafootnote]
- Bernstein, Paula, M.D., Ph.D., et. al. (2014 September). “When to have sex if you want to get pregnant.” Retrieved from http://www.babycenter.com/0_when-to-have-sex-if-you-want-to-get-pregnant_1809.bc ↩
- Wilcox, Allen J. M.D., Ph.D., Clarice R. Weinberg, Ph.D., and Donna D. Baird, Ph.D. (1995) Timing of Sexual Intercourse in Relation to Ovulation – Effects on the Probability of Conception, Survival of the Pregnancy, and Sex of the Baby. Retrieved from http://www.nejm.org/doi/full/10.1056/NEJM199512073332301 ↩